/*
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html.
 *
 * This file is a derivative of code released under the terms listed below.
 *
 */
/*
 * Copyright (c) 2009-2012,
 *
 * <p>Galois, Inc. (Aaron Tomb <atomb@galois.com>, Rogan Creswick <creswick@galois.com>, Adam
 * Foltzer <acfoltzer@galois.com>) Steve Suh <suhsteve@gmail.com>
 *
 * <p>All rights reserved.
 *
 * <p>Redistribution and use in source and binary forms, with or without modification, are permitted
 * provided that the following conditions are met:
 *
 * <p>1. Redistributions of source code must retain the above copyright notice, this list of
 * conditions and the following disclaimer.
 *
 * <p>2. Redistributions in binary form must reproduce the above copyright notice, this list of
 * conditions and the following disclaimer in the documentation and/or other materials provided with
 * the distribution.
 *
 * <p>3. The names of the contributors may not be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * <p>THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY
 * WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.scandroid.synthmethod;

import com.ibm.wala.core.util.strings.Atom;
import com.ibm.wala.ipa.summaries.MethodSummary;
import com.ibm.wala.ssa.SSAInstruction;
import com.ibm.wala.types.TypeReference;
import com.ibm.wala.util.collections.HashMapFactory;
import java.io.ByteArrayOutputStream;
import java.io.UTFDataFormatException;
import java.util.List;
import java.util.Map;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import org.w3c.dom.DOMException;
import org.w3c.dom.Document;
import org.w3c.dom.Element;

public class XMLSummaryWriter {

  //
  // Define XML element names
  //
  static final String E_CLASSLOADER = "classloader";
  static final String E_METHOD = "method";
  static final String E_CLASS = "class";
  static final String E_PACKAGE = "package";
  static final String E_CALL = "call";
  static final String E_NEW = "new";
  static final String E_POISON = "poison";
  static final String E_SUMMARY_SPEC = "summary-spec";
  static final String E_RETURN = "return";
  static final String E_PUTSTATIC = "putstatic";
  static final String E_GETSTATIC = "getstatic";
  static final String E_PUTFIELD = "putfield";
  static final String E_AALOAD = "aaload";
  static final String E_AASTORE = "aastore";
  static final String E_GETFIELD = "getfield";
  static final String E_ATHROW = "throw";
  static final String E_CONSTANT = "constant";

  //
  // Define XML attribute names
  //
  static final String A_NAME = "name";
  static final String A_TYPE = "type";
  static final String A_CLASS = "class";
  static final String A_SIZE = "size";
  static final String A_DESCRIPTOR = "descriptor";
  static final String A_REASON = "reason";
  static final String A_LEVEL = "level";
  static final String A_WILDCARD = "*";
  static final String A_DEF = "def";
  static final String A_STATIC = "static";
  static final String A_VALUE = "value";
  static final String A_FIELD = "field";
  static final String A_FIELD_TYPE = "fieldType";
  static final String A_ARG = "arg";
  static final String A_ALLOCATABLE = "allocatable";
  static final String A_REF = "ref";
  static final String A_INDEX = "index";
  static final String A_IGNORE = "ignore";
  static final String A_FACTORY = "factory";
  static final String A_NUM_ARGS = "numArgs";
  static final String V_NULL = "null";
  static final String V_TRUE = "true";

  private final Document doc;
  private final Element rootElement;
  private Element clrElt = null;
  private Element pkgElt = null;
  private final Map<Atom, Element> classElts;

  public XMLSummaryWriter() throws ParserConfigurationException {
    DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance();
    DocumentBuilder docBuilder = docFactory.newDocumentBuilder();

    doc = docBuilder.newDocument();
    rootElement = doc.createElement(E_SUMMARY_SPEC);
    doc.appendChild(rootElement);
    classElts = HashMapFactory.make();
  }

  public String serialize() {
    ByteArrayOutputStream baos = new ByteArrayOutputStream();

    // write the content into xml file
    TransformerFactory transformerFactory = TransformerFactory.newInstance();
    // transformerFactory.setAttribute("indent-number", new Integer(4));
    try {
      Transformer transformer = transformerFactory.newTransformer();
      transformer.setOutputProperty(OutputKeys.INDENT, "yes");
      transformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "2");
      DOMSource source = new DOMSource(doc);

      StreamResult result = new StreamResult(baos);
      transformer.transform(source, result);
    } catch (TransformerException | IllegalArgumentException e) {
      e.printStackTrace();
    }

    // using the default encoding here, since the bytes were just written
    // with a default encoding...
    return baos.toString();
  }

  /**
   * Throws various exceptions if a problem occurred serializing this method.
   *
   * <p>No guarantees as to the state of the Document if an exception is thrown.
   */
  public void add(MethodSummary summary) throws UTFDataFormatException {
    // create a method element, and populate it's attributes:
    Element methElt;
    TypeReference methClass = summary.getMethod().getDeclaringClass();

    Atom clrName = methClass.getClassLoader().getName();
    Atom pkg = methClass.getName().getPackage();
    Atom className = methClass.getName().getClassName();
    Atom methodName = summary.getMethod().getName();

    methElt = doc.createElement(E_METHOD);
    methElt.setAttribute(A_NAME, methodName.toUnicodeString());

    String descriptor = getMethodDescriptor(summary);
    methElt.setAttribute(A_DESCRIPTOR, descriptor);

    // default is false:
    if (summary.isStatic()) {
      methElt.setAttribute(A_STATIC, "true");
    }

    // default is false:
    if (summary.isFactory()) {
      methElt.setAttribute(A_FACTORY, "true");
    }

    // summarize the instructions:
    List<Element> instructions = summarizeInstructions(summary);
    for (Element elt : instructions) {
      methElt.appendChild(elt);
    }

    // get an element to add this method to:
    Element classElt = findOrCreateClassElt(clrName, pkg, className);
    classElt.appendChild(methElt);
  }

  private Element findOrCreateClassElt(Atom classLoaderName, Atom pkg, Atom className)
      throws UTFDataFormatException {
    Element classElt = classElts.get(className);
    if (classElt == null) {
      Element pkgElt = findOrCreatePkgElt(classLoaderName, pkg);
      classElt = doc.createElement(E_CLASS);

      classElt.setAttribute(A_NAME, className.toUnicodeString());
      pkgElt.appendChild(classElt);
      classElts.put(className, classElt);
    }
    return classElt;
  }

  private Element findOrCreateClrElt(Atom classLoaderName)
      throws DOMException, UTFDataFormatException {

    if (clrElt == null) {
      clrElt = doc.createElement(E_CLASSLOADER);
      clrElt.setAttribute(A_NAME, classLoaderName.toUnicodeString());
      rootElement.appendChild(clrElt);
    }
    return clrElt;
  }

  private Element findOrCreatePkgElt(Atom classLoaderName, Atom pkg) throws UTFDataFormatException {
    if (pkgElt == null) {
      Element clrElt = findOrCreateClrElt(classLoaderName);
      pkgElt = doc.createElement(E_PACKAGE);
      pkgElt.setAttribute(A_NAME, pkg.toUnicodeString());
      clrElt.appendChild(pkgElt);
    }
    return pkgElt;
  }

  private List<Element> summarizeInstructions(MethodSummary summary) {
    SSAtoXMLVisitor v = new SSAtoXMLVisitor(doc, summary.getNumberOfParameters());

    for (SSAInstruction inst : summary.getStatements()) {
      inst.visit(v);
    }

    return v.getInstSummary();
  }

  /** Generate a method descriptor, such as (I[Ljava/lang/String;)[Ljava/lang/String; */
  private static String getMethodDescriptor(MethodSummary summary) {
    StringBuilder typeSigs = new StringBuilder("(");

    int i = 0;
    if (!summary.isStatic()) {
      i = 1; // if it's not static, start with param 1.
    }

    for (; i < summary.getNumberOfParameters(); i++) {
      TypeReference tr = summary.getParameterType(i);

      // unwrap array types
      while (tr.isArrayType()) {
        typeSigs.append('[');
        tr = tr.getArrayElementType();
      }

      if (tr.isPrimitiveType()) {
        typeSigs.append(tr.getName().toUnicodeString());
      } else {
        typeSigs.append(tr.getName().toUnicodeString()).append(';');
      }
    }
    typeSigs.append(')');

    TypeReference returnType = summary.getReturnType();
    if (returnType.isPrimitiveType()) {
      typeSigs.append(returnType.getName().toUnicodeString());
    } else {
      typeSigs.append(returnType.getName().toUnicodeString()).append(';');
    }
    return typeSigs.toString();
  }
}
